• Aim: How do we solve quadratic trigonometric equations?

At the end of the lesson, you will be able to...
1. solve quadratic equations either by factoring or by using the quadratic formula
2. solve quadratic equations for all values of the angles whose measures lie between 0° and 360°


This is basically solving a quadratic equation such as 2x^2 - 4x + 3 = 0. But you will find them written with a trig function such as
2sin^2 - 4sin + 3 = 0. Some may be able to be factored and others you will need to use the quadratic formula.

Here are two videos that explain each type:

Factoring


Using the quadratic formula


Be sure to use your graphing calculator for these. Also, most angles are positive in two quadrants and negative in two quadrants. You need to remember to list both angles when possible.

Is there a way to use your graphing calculator to do this? How? What are the steps ? Can these steps be applie dot lesson 18?

  • Homework:

Quadratic_Trig.JPG

  • Answers

A-Quadratic_Trig.JPG

  • Journal entry: How would the solution set of sin²a = 1 for 0<a<2pi differ from the solution set for sin²a = 1 for an unrestricted domain?